We at Språkbanken Text have just released a new corpus of native (L1) and non-native (L2) speech in four languages: English, Spanish, French and Italian. The corpus contains more than 170 million words produced by more than 97 thousand speakers (size varies a lot across the four languages, though).
Korp offers a lot of different corpus collections for various types of search (and research). Swedish as a Second Language (L2) is one of the subcategories of the language that can be studied with the help of Korp. At the moment, Korp provides access to five L2 corpora through its interface: